1. Field of the Invention
The present invention relates to an electricity storage device. Further, the present invention relates to an electricity storage device container and electricity storage device packaging material.
2. Description of Related Art
Secondary batteries are typical electricity storage devices. Because of the rapid growth of electronic device fields such as mobile phones and portable computers, the demand for secondary batteries such as light and small lithium-ion batteries has increased. As packages for secondary batteries, metal cans have been used in the past. However, packaging materials formed by laminating plastic films and metal foils and so on have been entering the mainstream in view of their lightness and productivity.
Examples of the simplest packaging materials include a laminate having, from the outer layer side thereof, an outer layer side resin film layer 11, an outer layer side adhesive layer 12, a metal foil layer 13, an inner layer side adhesive layer 14, and a heat seal layer 15 as shown in FIG. 1. As shown in FIG. 2, a battery container is molded from the above-described packaging material (i.e., performing deep-draw molding, stretch-expand forming, or the like) in such a manner that the outer layer side resin film layer 11 forms a convex surface and the heat seal layer 15 forms a concave surface. Then, a battery is manufactured by encapsulating electrodes, an electrolyte solution, and the like on the concave surface side of the battery container and accommodating the battery container.
Further, a capacitor is also a type of electricity storage device. In particular, the lithium-ion capacitor field is one whose market is expected to grow in the future.
Patent Literature 1 (Japanese Unexamined Patent Application Publication No. H08-193148) discloses an adhesive resin composition containing, in a specific ratio, (A) a polyolefin-based resin including at least one type of a functional group selected from a group consisting of an acid anhydride group, a carboxyl group, and a metal carboxylate, and (B) an epoxy compound including at least two epoxy groups and having a molecular weight of 3,000 or lower.
Patent Literature 2 (Japanese Unexamined Patent Application Publication No. 2012-216364) discloses a package for a battery including an adhesive layer containing, in a specific ratio, an acid-modified polypropylene resin containing 70 mass % or more of a propylene component and 0.1 to 10 mass % of an acidic component, and a cross-linking agent including at least one of an oxazoline compound and an epoxy compound.
Patent Literature 3 (Japanese Unexamined Patent Application Publication No. 2013-91702) discloses an adhesive resin composition containing an acid-modified polyolefin resin (A), and an epoxy resin compound (B) including at least two epoxy groups in one molecule and at least ten hydroxyl groups in one molecule.
Patent Literature 4 (International Patent Publication No. WO2014/050686) discloses a lamination adhesive composition containing a polyolefin resin (A) including a hydroxyl group and/or an acid group, a phosphoric-acid-modified compound (B), and an epoxy resin (C) having an epoxy equivalent weight of 160 to 1,000 (claim 4). Further, Patent Literature 4 discloses application of the lamination adhesive composition to a laminate for a secondary battery (claim 9).
Patent Literature 5 (Japanese Unexamined Patent Application Publication No. 2006-307104) discloses an adhesive composition including: a main agent containing maleic-acid-modified chlorinated polypropylene, phosphate, ultra-fine particles silane, and an organic solvent; and a curing agent containing a silane coupling agent, and an epoxy resin and/or polyisocyanate. It is mentioned that the addition of ultra-fine particles silane prevents precipitation of phosphate, thus making it possible to improve the application property of the adhesive composition.